Improved accessibility in graphs in reports

In the reports section of JSM, the graphs (which are also used in Jira dashboards) could use some additional features to improve accessibility.

Primarily, the only options to identify a series in the graph is the color. However, this is not great for people with full or partial color-blindness. We've adjusted by picking a couple very light and dark colors, but that's not an optimal solution and won't work for all users.

There are a couple of solutions such as offering a few line patterns (solid, dashed, dots, etc.), or picking a symbol for the value nodes, which would improve usability for everyone.

Thanks!